1. Field of the Invention
This invention relates to an improved endotracheal tube connector that provides for sampling of respiratory gases, measuring of respiratory gas pressure, or respiratory flow of the patient.
2. Background Discussion
Respiratory apparatus is commonly employed to assist a patient in breathing. This apparatus, called a ventilator, is connected to two main lines which are independently connected into the two separate branched arms extending outwardly from the junction of a Y-tube. It is common practice to use an adaptor inserted into the open stem of the Y-tube to connect the Y-tube to an endotracheal tube extending from the trachea of a patient.
Different devices are sometimes employed when a patient is on a ventilator: One for measuring the respiratory pressure of exhaled gas, one for measuring composition of the exhaled gas, and one for measuring the respiratory flow of the patient. The patient's respiratory flow is the volume of gas the patient inhales and exhales in a given time period, and is usually expressed in liters per minute.
The respiratory flow is determined by measuring the change in pressure of this gas as it flows past a restriction in a tubular member. The tubular member is called a pneumotach. Such a pneumotach is described in the American Society of Anesthesiologists publication "Anesthesiology," Vol. 51, No. 2, pp. 149-153 entitled "Pneumotachography," by Saklad, Sullivan, Palitotta, and Lipsky. It consists of a main tube having a restriction therein and connecting tubes extending outwardly from this main tube on opposite sides of the restriction. There is a change in pressure as gases flow along the tube past the restriction, and this change is indicative of the respiratory flow of the patient.
In accordance with conventional practice, when any one of these devices are connected to the Y-tube, a substantial amount of dead space results. As explained in greater detail below, this dead space is highly undesirable and not only interferes with obtaining an accurate sampling of gases, but can present a health hazard to very small patients such as newborn babies. Moreover, the way these devices are connected is unsatisfactory because there is a high probability that they will become accidentally disconnected.